The present invention relates to thin, flat zinc anodes for galvanic cells and batteries and to batteries employing such anodes. More particularly, the present invention relates to thin, flat anodes produced from zinc dust and a small amount of polymeric binder.
In recent years there has been increasing demand for reliable, compact batteries, particularly for use in portable electrically operated devices such as tape recorders, radios, cameras, etc. Historically, most batteries produced for use in such devices have been cylindrical and this has to some extent limited the size and shape of the devices in which they are used. In modern design concepts, there is increased emphasis placed upon devices having thin, flat shapes which do not satisfactorily accommodate the conventional cylindrical batteries. This emphasis upon thin, flat cells and batteries has, of course, imposed corresponding restrictions upon the size of the anodes and other cell elements. In general, zinc anodes have either been cast or fabricated from sheet metal. It has also been proposed to produce zinc anodes from powdered zinc mixed with binder resin and compressed at elevated temperatures and high pressure. Casting and high temperature and pressure compression techniques are undesirable to produce very thin, flat zinc anodes. While sheet metal anodes have met with a degree of success in such uses, they are not fully satisfactory particularly when very thin anodes are desired. Attempts to employ a polymeric latex as a vehicle for zinc particles was also unsatisfactory since the mixture of the latex and the zinc particles lacks stability resulting in separation or agglomeration to a degree that renders the mix unusable.